Apparatus for the application of diathermy current



Feb. 11', 1930. QECAMPBELL 1,746,379

APPARATUS FOR THE APPLICATION OF DIATHERMY CURRENT Filed July 7, 1927 Patented Feb. 11, 1930 UNITED STATES CHARLES E. CAMIBELL, on LYNN, MASSACHUSETTS, Assrenou .ro o. CAMPBELL, or

PATENT foFFIcE LYNN, MASSACHUSETTS APPABATUS FOR THE APPLICATION OF DIATHERMY CURRENT Application filed July 7,

trodeparticularly adapted for use inthe ap- 10 plication of diathermy current which is durable, practical and highly efficient in operation and with which objectionable sparking may be reduced to a minimum.

With these objects in View and such others 15 as may hereinafter appear, the inventionconknown respects. i to pass through the portion of the body to be U tribution of the e,

sists intheapparatus andin thestructures, arrangements and combinations of parts here inafter describe-dand claimed.

Inthe drawing illustrating the preferred embodiment of the invention, Figure 1 is a side elevation illustrating the use ofapparatus embodying the present invention; Fig. 2 is a vertical section on line 22 of Fig; 1 viewed in the direction of the arrows; Fig.

3 1s a detail in side elevation illustrating the present apparatus with electrodes of difierent size for securing localized effects of different intensities; and Fig. 1 is a vertical sectional detail illustrating the preferred manner of mounting an electrode.

Attempts have heretofore been made to device apparatus for use inthe application of diathermy current, but as far as I am aware V such attempts have not proved satisfactory "in, practice." The use of such current possesses therapeutic value in assisting the procass of bone knitting, as inthe case of fractures, in assisting blood circulation, and in other The current has been caused treated,from electrodes composed of block tin or composition foil and insome instances of metalliomesh used over rubberspongeaand in practice the electrodes are applied in direct contact with the tissue upon opposite sidespof theportion {of the body through which the current is to pass. Bothtypes of electrodes possess aTtendency-to oxidize and the o d t us ormed. p event a un t mdis with, theirs- 1927'. Serial No. 203,938.

sult that undesirable sparking takes place. This sparking has resulted in uncomfortable sensations to thepatient and in some instances has caused burns. The block tin or composition foil electrodes after a certain period of use become rough over their surface and the uneven distributionof current density which necessarily follows causes sparking. This fact, together with the tendency of the metal to oxidize, renders the use of these forms of electrodes unsatisfactory in practice. The mesh type of electrode tends to corrode be tween the individual mesh units, causing sparking between the same. In addition these meshelectrodes are not as sanitary as might bedesired and may be only properly sterilized with difficulty. 1

In accordancewith the present invention,

the apparatus for applying diathermy current is provided with an electrode and preferably two electrodes of such design and whose cont-acting surface is of such composition as to eliminate the objectionable sparking above referred to. Provision is also preferably made for removably mounting the electrodes upon electrode supporting members to theend that the electrodes may be easily sterilized and cleaned, and also in order that electrodes of differentsize may be used in order to produce localized diathermic efiects of varying intensities. The preferred form of electrode contemplates a contacting surface of cup shape which functions'when the electrode is firmly pressed against the tissue, to produce a vacuum effect holding the tissue in firm contact with the electrode.

Referring now to the drawing, the apparatus illustrated therein comprises two electrode supporting members 10, 12 preferably of insulatingmaterial such as wood, and which are provided with suitable slots 13, 14 for the reception of a cross support, 15 upon which the electrode supporting members 10, 12 are slidably mounted to constitute a unit. The electrode supportingmiembers, I

10, 12 at their upper ends are arranged to support plate electrodes 20, 21 in operative position for engagement with the, opposite surfaces of the portion of the body to be treated, ea lier? Purp ses of il r ion n Fig. 1 the electrodes 20, 21 are illustrated as en aging the opposite sides of a knee.

rovision is made for operatively connect ing the electrodes with lead wires 22, 2st leading from the usual high frequency machine (not shown), and the leadwires 22, 24 are preferably pressed through guide holes in the electrode supporting members 10, 12 whereby the wires aremaintained in a position out of contact with the patient. As illustrated in Fig. 1 and in detail in Fig. 4, each one of the electrodes 20, 21 is operatively supported upon its electrode supporting member by means of a bolt25 extended through a hole in the electrode supporting member and having a shoulder 26 which engages one surface thereof and upon whose threaded end 27 the usual form of terminal post 28- is vscrewed to rigidly hold the bolt in operative position. The terminal post 28 is provided with the usual hole 29 for the reception of the end of the lead wire and afirm connection is made by means of the thumb screw 30. The bolt 25 is provided with a spring socket 32 for the reception of a ball 34 formed integrally upon the rear face of the electrode to thereby permit the electrode to be readily removed or installed in operative position. The ball and socket connection between the electrode and its supporting member enables the electrode to adapt itselfto different positions during the use of the apparatus as will be described. r

In order to avoid objectionable sparking, each plate electrode 20, 21 is preferably formed in the shape illustrated in Fig. 4 and with a contacting surface of such composition as to reduce the insulating effect of oxidation to a minimum. In practice I prefer to form the electrode of brass with the contacting surface silver plated. As herein shown, the contacting surface of each plate electrode is cup shaped and the marginal portion 36 thereof is rolled back in a direction away from the contacting face, so that when such an electrode is applied to the tissue and firmly pressed against the same a partial vacuum is formed, the effect of which operates to draw the tissue into close and firm contact with the surface of the electrode forming an ideal contact. a The fact that the edge of the electrode is rolled back out of contact with the tissue serves to prevent any concentration of current at the edge and consequently enables a uniform distribution of current density to be had over the contacting surface of the electrode with the result that a minimum tendency toward sparking exists.

In the use of the apparatus, the ball and socket connection between the electrode and thesupporting member enables the electrodes to adapt themselves to different and irregular angles of the body and facilitates obtaining proper cont-act between the electrode and the tissue. The fact-tl1at the electrodes may be readily removed not only facilitates the cleaning and sterilization of the electrodes but also enables electrodes of different sizes to be utilized, depending upon the portion of the body to be treated. In this connection it is possible by utilizing electrodes of different sizes, as illustrated in Fig. 3, to secure varying intensities of localized diathermic eflect. By using an electrode of relatively large area on one side and an electrode of relatively small area on the other side, it is possible to produce a concentrated efiect near the smaller electrode.

By the use of the present apparatus, the current produced from many machines now in use and considered impractical due to the uncomfortable sparking may be used, and in the use of the apparatus bandages and other instrumentalities which have heretofore been used for obtaining effective contact will be found to be unnecessary.

It is well-known that some metals when they become oxidized have the property of insulating or interfering with an electric cir- .cuit, while there are some oxides while not being exactly an insulator interfere with the passage of the current in one direction, having a rectifying effect, such as the oxide of copper. Inasmuch as the device herein de scribed is usedprimarily with currents of high frequency, it is quite important that the contacting surface of the electrodes be of such substance that the oxide will not rectify or insulate the current; r If rectification is produced, it interferes with the true heating effects in the body that the high frequency current is intended to give, and if the electrodes partially insulate, some of the lower potential oscillations of the high frequency current will not pass through directly as they are generated from the machine, and an accumulated charge will be built up in the plate electrodes, acting as condensers, and occasionally a discharge of this current will take place giving a very erratic and uncomfortable effect from the high frequency current, even though the generator of the same is working satisfactorily.

While it is preferred to embody the different features of the present invention in apparatus of the form illustrated herein, nevertheless it is to be understood that they may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is 1. An apparatus for the application of diathermy current comprising two elec trode supporting members, and an electrode mounted upon each supporting member and consisting of a metallic plate provided with a concave contacting face and a surrounding rim portion curved back from said face to form a con'vex'rim extending entirely around said concave contacting face.

2. In an apparatus for the application of diathermy current, an electrode supporting member and an electrode mounted thereon comprising a metallic member having its contacting face concave and its entire edge rolled back to form an annular convex edge portion and provided with a metallic surface of a character such that upon oxidation no insulating elfect is produced whereby substantially uniform current density over the cont-act mg surface is insured.

S. In an apparatus for the application of diathermy current, an electrode supporting member, and an electrode mounted thereon comprising a conducting plate providedwith a shallow spherically concave face and with the edge portions thereof surrounding said concavity, rolled back to form an annular convex edge portion to thereby prevent sparking at the edge.

4. As a new article of manufacture, a plate electrode for use in the application of diathermy current comprising a circular disk of contacting material having its contacting face slightly concave and having its entire edge portionrolled back to form a convex annular edge portion whereby substantially uniform distribution of current density is obtained over the entire contacting surface.

5. As a new article of manufacture a plate electrode for use in thefapplication of diathermy current comprising a circular metal disk provided with a shallow concave contacting face and with an annularconvex edge portion surrounding said concave contacting face, and having the contacting face silver plated. l

6. The combination with an electrode supporting arm, of a plate electrode, and means for removably supporting the plate electrode upon said arm including a bolt extended through the arm, a therminal post screwed upon the end of the bolt, a socket member upon one end of the bolt, and a ball attached to the electrode and received within the socket member.

7. The combination wlth an electrode supporting arm, of a plate electrode, and means for supportingthe electrode upon the arm including a bolt extended through the arm. a terminal post screwed upon the end of the bolt, and a ball and socket connection between the second end of the bolt and the-electrode. V a i 8. As a new article of manufacture, a plate electrode for use in the application of diathermy current comprising a plate of contacting material having its contacting face slightly concave and having its entire edge portion convex and rolled back whereby substantially uniform distribution of current density is obtained over the entire contacting surface.

Inltestimony whereof I have signed my name to this specification. :0 l

CHARLES E. CAMPBELL. 

